The direct conversion of hemicelluloses to selectively produce xylose from corn stover catalysed by maleic acid

Abstract

The direct conversion of hemicellulose in corn stover to xylose while avoiding further degradation in water by using maleic acid as a catalyst was studied. When 0.06 M maleic acid was added, a 96.8 wt.% hemicellulose conversion was achieved, with relatively low conversion of cellulose (24.1 wt.%) and lignin (20.7 wt.%) at 140 °C for 2 h, and a relatively high yield of 22.5 wt.% (95.5 mol%) to xylose was achieved. Maleic acid interacted with the open form of xylose via hydrogen bonding to stabilize xylose, whereas its further degradation pathway was blocked, which led to improved yield and selectivity. The conversion of hemicellulose in bamboo, apple tree, straw, and mulberry to produce xylose (at 140 °C, for 2 h) catalyzed by maleic acid was also effective (Y a = 17.8 wt.%, Y b = 127.1 mol% xylose yield for hardwood and Y a = 25.1 wt.%, Y b = 109.6 mol% yield for grass) under the same conditions.